Los Alamos scientists recently demonstrated a new laser-based technique for producing a burst of neutrons capable of revealing the presence of illicit nuclear materials, such as plutonium. “No one knew it could actually be done,” said Andrea Favalli, one of the team leaders, “until we worked out the details, fabricated the parts, and performed the test.” The system is fast, reliable, and portable enough to be used for screening at U.S. ports, border checkpoints, and other sensitive areas.